Fixing an audio card shorted capacitor with software solution

Question

Recently one of the capacitors on my MB in the integrated Realtek HD audio card shorted. I cannot identify and solder another capacitor, because they are very tiny SMD elements. Despite this being a hardware problem, it can be fixed using audio filter software. I am having an FFT peak at 9322Hz and when I generate a 180-degree shifted digital sinewave using my personal copy of the soundcard scope software, the peak in the FFT graph disappears. I need a program which can:

1. Create custom amplitude-frequency graph to cut-off the 9 KHz using low-pass and high-pass filters.
2. Prefer to be an open-source project, so I can contribute, but an end-user program is also OK.
3. Processes the data from the sound card, so I can use its output to loop back the audio.
4. Sits and interacts between the application making a request to the sound card and the sound card itself.
5. Sends the filtered audio to the sound card rather than the original audio
6. I can easily design a filter, but I lack the program which can interface my filter design.

I can provide more information in 3-4 hours.